9545

• UCREFRP Catalog Number: 9545
• Author: Chart, T. E. and L. Lentsch.
• Title: Flow Effects on Humpback Chub ‎(Gila cypha)‎ in Westwater Canyon - Final Report.
• USFW Year: 1999.
• USFW - Doc Type: Aspinall-46,
• Copyright Material: NO

LIST OF FIGURES (continued)
Figure 10. Percentage of sampling effort expended in each low velocity habitat type and
corresponding relative abundance of YOY Gila spp. in three sampling subreaches of
Westwater Canyon. Data collected in July and August, 1992,1994, and 1996; July -
September,1993 and 1995 .................................................. 43
Figure 11. Availability of backwater and embayment habitat in Westwater Canyon, Colorado River;
1992-1996, plotted against flows at the time of sampling (L1SGS Stateline gage) ....... 44
Figure 12. Project mean CPEs (with S.E. bars) for the three most common non-native cyprinids
collected throughout the study; 1992 - 1996. Data presented for each of three sampling
sub-reaches in Westwater Canyon, Colorado River .............................. 45
Figure 13. Relative abundance of three cohorts (1992, 1993, and 1994) of chubs collected in
Westwater Canyon, Colorado River; 1992-1996. Age 0 CPE reads off the primary
Y-axis and represents catch from the dates indicated as well as the size of the YOY at
that time; data is from the canyon sub-reach only. Age 1+ and 2+ read off the secondary
y-axis and represents a mean catch of the two fish community trips that year -all sites
combined ............................................................... 46
Figure 14. Species composition of fish collected with electrofishing in Westwater Canyon at three
sampling sites; 1992 - 1996, combined. See Appendix Table 1 for species abbreviations.
Incidental species (comprised < 1% of the total catch) not depicted: FM x WS, SD, GS,
LMB, SMB, BB, BC, BrT, RS, FH, SS, FM x BH ............................... 47
Figure 15. Species composition offish collected with trammel nets in Westwater Canyon at three
sampling sites; 1992 - 1996, combined. See Appendix Table 1 for species abbreviations 48
Figure 16. Humpback Chub trammel net CPE (fish / 23 m net hour) as collected at three sampling sites
in Westwater Canyon, Colorado River; 1992 -1996. The July, 1994, and July, 1996, trip
results are circled due to the relatively strong catch of humpback chub ............... 49
Figure 17. Roundtail Chub trammel net CPE (fish / 23 m net hour) as collected at three sampling
sites in Westwater Canyon, Colorado River; 1992 -1996. The July, 1994, and July, 1996,
trip results are circled due to the relatively strong catch of humpback chub (compare with
Figure 14) ............................................................... 50
Figure 18. An analysis of humpback chub movements as determined through recapture of PIT tagged
individuals in Westwater Canyon, Colorado River; 1992 - 1996 .................... 51
Figure 19. An analysis of roundtail chub movements as determined through recapture of PIT tagged
individuals in Westwater Canyon, Colorado River; 1992 - 1996 .................... 52
Figure 20. Persistence as measured by length of time between individual captures for humpback chub
tagged in Westwater Canyon 1992-1996. Sample size in legend refers to numbers of fish
PIT tagged each year ...................................................... 53
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